The primary emphasis of the work centers around the ability of regenerating urodele limbs to accumulate adrenocorticosteroids in distal regions. We are examining the mechanisms underlying this phenomenon, e.g. is a steroid binding protein involved, and if so, the nature of its properties, and the location of binding in various cell types. We are also exploring the metabolic fate of various labelled adrenocorticosteroids with respect the binding phenomenon; it appears that the primary steroids active in accumulation are not the same as the one injected intraperitoneally (H3 corticosterone). The phenomenon is dependent on an intact nerve supply to the limb, and we are interested in the nature of this dependancy. A secondary emphasis centers around ultrastructural and histochemical examinations of smooth, myotomal, and limb musculatural with respect innervation and the various roles nerve plays with respect differentiation, maintenance, and dedifferentiation of these basic muscle types.